ADU Rules by City in Southern California (2026)

An accessory dwelling unit (ADU) is a second, self-contained home on the same lot as your house, with its own kitchen, bathroom and entrance. As of 2026, California ADU law (Government Code 66310–66342) guarantees the same floor in every city: a detached ADU of at least 800 square feet and 16 feet tall with 4-foot side and rear setbacks, approved within 60 days with no hearing, no parking for a conversion and no owner-occupancy condition. Everything above that floor differs by city, and that is what this page compares. Green Design and Build is a licensed general contractor (CSLB #1110975) based in Van Nuys, serving homeowners across Los Angeles County, Orange County, Ventura County, western Riverside County and western San Bernardino County.

Who we are

Green Design and Build is led by Dekel Sofer. We hold a 4.7-star rating across 146 Yelp reviews and have completed hundreds of projects. We are a full-service residential general contractor and design-build remodeler, not an ADU specialist: we build ADUs and garage conversions alongside kitchens, bathrooms, additions and whole-home renovations.

What state law guarantees in every city

A city may be more generous than the rules below; it may not be stricter.

• An 800 sq ft detached ADU on any lot with a house, with 4-foot side and rear setbacks (Government Code 66323); no lot-coverage, floor-area, open-space, front-setback or lot-size rule can block it (66321).
• Height of at least 16 feet detached, 18 feet within half a mile of a major transit stop or on a multi-story multifamily lot, plus 2 feet for roof pitch; 25 feet or the zone limit for an attached ADU.
• Local size caps of at least 850 sq ft for a studio or one-bedroom and 1,000 sq ft for two or more bedrooms; the statewide detached ceiling is 1,200 sq ft.
• A junior ADU of up to 500 sq ft inside the walls of the house. Since January 2026, owner-occupancy applies to a JADU only when it shares a bathroom with the house.
• No owner-occupancy for ADUs (Government Code 66315); AB 976 made the prohibition permanent.
• Rentals longer than 30 days. A city may require it, and all nine cities here do.
• A 60-day clock. 15 business days to confirm completeness, then 60 days to approve or deny with no hearing, or the application is deemed approved (66317).
• No impact fees at 750 sq ft or less, proportional above; school fees only above 500 sq ft.
• Conversions keep their setbacks and their parking. An ADU inside an existing house or garage needs no new setback, may grow by up to 150 sq ft solely for entry and exit, never replaces lost parking, and cannot be made to take a separate utility connection. Fire sprinklers follow the main house.
• Unit combinations. A single-family lot must be allowed one conversion ADU, one JADU and one new detached ADU of up to 800 sq ft.
• HOAs cannot say no. Under Civil Code 4751, a CC&R that prohibits or unreasonably restricts an ADU or JADU is void; reasonable design conditions still apply.

Side by side: ADU rules in nine Southern California cities

The table condenses the city pages below into one view. Every figure is the city rule as published on that city’s page on this site, with the state-law floor noted where it overrides a stricter local number. Click a city for the full rules, fee details and where to apply.

City	Detached ADU, max size	JADU	Detached height	Side / rear setbacks (new build)	Parking	Impact fees	Decision deadline
Los Angeles	1,200 sq ft (ordinance); 800 sq ft guaranteed by state law on any lot	500 sq ft inside the house	16 ft; 18 ft near major transit (+2 ft roof pitch)	4 ft; none for conversions	None for a state-law ADU; ordinance ADU 1 space unless exempt	None at or under 750 sq ft; proportional above	60 days after a complete application
Glendale	1,000 sq ft (850 sq ft with one bedroom)	500 sq ft inside the house	16 ft; 18 ft near transit (+2 ft)	4 ft; none for conversions or same-footprint rebuilds	1 space per unit or bedroom, whichever is less, unless exempt	Exempt under 750 sq ft; proportional above	60 days
Pasadena	1,200 sq ft; 1,000 sq ft in the Hillside Overlay; 800 sq ft on narrow hillside streets	500 sq ft, house or attached garage	18 ft and two stories; 16 ft in hillside and historic cases	4 ft; none for conversions	Not required for conversions, near transit, historic districts or near car-share; otherwise 1 space	Waived up to 900 sq ft (since 17 July 2025)	60 days
Burbank	850 sq ft studio/one-bedroom; 1,000 sq ft with more bedrooms; 800 sq ft in the Mountain Fire Zone	500 sq ft, house or attached garage	17 ft; 18 ft (+2 ft) near major transit	4 ft; conversions keep existing setback	Up to 1 space, tandem allowed; none near transit or for conversions	None under 750 sq ft; proportional above; school fees above 500 sq ft	60 days (city guidance: first review up to 8 weeks)
Santa Clarita	850 / 1,000 sq ft by bedroom count; 800 sq ft cannot be denied	500 sq ft inside the house	16 ft; 18 ft (+2 ft) near major transit	4 ft; none for conversions	None for conversions, JADUs or an 800 sq ft state-standard unit	None under 750 sq ft; Bridge and Thoroughfare fee from 750 sq ft	60 days
Thousand Oaks	800 sq ft state-guaranteed unit plus one larger local-standard ADU	500 sq ft inside the house	16 ft; 18 ft (+2 ft) near major transit	4 ft; conversions keep existing setbacks	None for conversions or near transit; otherwise at most 1 space	None under 750 sq ft; school fees from 500 sq ft	60 days
Irvine	1,200 sq ft; 800 sq ft guaranteed on any lot	500 sq ft, house or attached garage	16 ft; 18 ft (+2 ft) near major transit	4 ft; none for conversions	At most 1 space; none near transit or for conversions	None under 750 sq ft; proportional above	60 days
Anaheim	1,200 sq ft (minimum 150 sq ft)	500 sq ft inside the house	18 ft (+2 ft pitched roof) or the main house height, whichever is greater	4 ft; 10 ft from the main house; conversions exempt	Studio none; 1 space with bedrooms unless exempt	None under 750 sq ft; proportional above	60 days
Corona	1,200 sq ft	500 sq ft inside the house	State floor: 16 ft; 18 ft near major transit	4 ft; none for conversions	1 space per unit or bedroom, whichever is less; none for conversions or near transit	None at or under 750 sq ft; proportional above	60 days

Recent rule changes reflected in this table

• State, 1 January 2026: owner-occupancy for a JADU may only be required where the JADU shares a bathroom with the main house (Gov. Code § 66333). Reflected in every city row.
• Anaheim, January 2026: ADU ordinance (AMC 18.38.015 and 18.42.030) amended; detached height now 18 ft plus 2 ft for a pitched roof, or the main house height.
• Pasadena, 17 July 2025: Residential Impact Fee waived for ADUs up to 900 sq ft.
• Los Angeles: owner-occupancy for ADUs cannot be required (AB 976 made the 2020 change permanent); park fees and the Affordable Housing Linkage Fee are not charged on ADUs.

Publishers, planners and homeowner groups are welcome to reproduce this table with a link to this page. If you spot a city rule that has changed, email info@greendesignandbuild.com and we will review it.

ADU rules by city

Values come from each city’s ordinance or ADU page as checked in September 2026 and cited on the linked city pages. “Height” is the detached limit; every city also allows 18 feet plus 2 feet near major transit and 25 feet attached unless a higher figure is shown. Parking rules and where to apply are on each city page.

City	Max detached ADU	Detached height	Pre-approved plans
Los Angeles	1,200 sq ft ordinance ADU; 800 sq ft by right	16 ft state-law unit; zone height for an ordinance unit	Yes: LADBS Standard Plan Program (free 455 sq ft YOU-ADU)
Glendale	1,000 sq ft (second bedroom over 850)	16 ft, two stories	Yes: one 740 sq ft city plan
Pasadena	1,200 sq ft; 1,000 in the Hillside Overlay	18 ft; 16 ft in the Hillside Overlay	Yes: Prototype A, 374 sq ft studio
Burbank	850 sq ft; 1,000 with two+ bedrooms; 800 in the fire zone	17 ft; 23 ft above a garage	Yes: BPAP 432 sq ft studio
Santa Clarita	850 sq ft; 1,000 with two+ bedrooms; 800 by right	16 ft	No
Thousand Oaks	800 sq ft by right; larger local unit up to 1,200	16 ft	Yes: ADU Plans Gallery
Irvine	1,200 sq ft (state law applies)	16 ft	Listed as coming soon
Anaheim	1,200 sq ft	18 ft plus 2 ft for a pitched roof	Yes: ADU Express, four free plans
Corona	1,200 sq ft	16 ft	Program created; no plans yet

Los Angeles

Los Angeles runs two tracks: the state-law ADU (800 sq ft, 16 feet, no parking) and the ordinance ADU under LAMC 12.22 A.33, detached up to 1,200 sq ft and two stories. Hillside fire zones, HPOZ historic districts and the Coastal Zone are the local twists. Read the Los Angeles ADU rules, our guide to the LADBS standard plans, and our Los Angeles contractor page.

Glendale

Glendale caps ADUs at the state minimums, 850 sq ft with one bedroom and 1,000 with two, adds objective design standards for new construction, and asks you to clear the unit’s location with Glendale Water & Power before drawing. See the Glendale ADU rules and our Glendale page.

Pasadena

Pasadena allows 1,200 sq ft at 18 feet and two stories, but the Hillside Overlay cuts that to 1,000 sq ft and 16 feet, and landmark districts keep a non-exemption ADU out of view from the street. Its Residential Impact Fee is waived up to 900 sq ft. See the Pasadena ADU rules and our Pasadena page.

Burbank

Burbank is more generous on height (17 feet, 23 feet above a garage, 30 feet attached) but caps size at 850 or 1,000 sq ft and requires rental terms longer than 90 days. The Mountain Fire Zone drops the cap to 800 sq ft; the R-1-H Rancho district allows conversions only. See the Burbank ADU rules and our Burbank page.

Santa Clarita

Santa Clarita rewrote its ordinance in April 2026 after the state found the earlier version out of compliance; the city standard is 850 or 1,000 sq ft by bedroom count, and every plan is routed past Urban Forestry for protected oaks. Stevenson Ranch, Castaic and Val Verde are county jurisdiction. See the Santa Clarita ADU rules and our Santa Clarita page.

Thousand Oaks

Thousand Oaks publishes a pre-approved plan gallery and the TO/24 portal, and its Article 45 ordinance keeps ADUs off slopes steeper than 25 percent and outside oak protected zones; fire-zone lots build to Chapter 7A. See the Thousand Oaks ADU rules and our Thousand Oaks page.

Irvine

Irvine’s 2018 ordinance was found non-compliant on 29 points in January 2025, so the city applies the state standard; the practical gatekeeper is the village architectural committee, which reviews design but cannot refuse the unit. See the Irvine ADU rules and our Irvine page.

Anaheim

Anaheim pairs the 1,200 sq ft cap with an 18-foot detached height, a free four-plan ADU Express catalogue that can issue a permit within a day for an eligible address, and its own utility, Anaheim Public Utilities, which needs a meter spot report before you submit. See the Anaheim ADU rules and our Anaheim page.

Corona

Corona’s Chapter 17.85, rewritten in March 2025, follows the state framework almost word for word, with a 1,200 sq ft detached cap and up to two ADUs on a lot; the real variables are expansive clay soils, fire zones against the Cleveland National Forest and HOA review in South Corona. See the Corona ADU rules and our Corona page.

Cities we build in that do not have a page yet

State ADU law applies in every one of them: the 800 sq ft detached unit, 4-foot setbacks, the 60-day clock, no owner-occupancy and no replacement parking for a garage conversion. What we check during the site walk is the local ordinance on top, because each city runs its own building division with its own caps, design standards and portal: Long Beach and Torrance in Los Angeles County, Simi Valley in Ventura County, and Riverside and Murrieta in western Riverside County. We add a city page once its ordinance has been verified against the state floor; until then, our service areas cover how we work there.

How to use the calculator

Our California ADU rules calculator asks whether the lot has a house, whether it is single-family or multifamily, how close it is to transit, and whether you are converting or building new, and returns the state-law floor no city can deny. The calculator gives the minimum you are guaranteed; the city page gives the local maximum.

What an ADU costs

Our published budgeting ranges, which are not quotes, apply across all nine cities: a garage conversion ADU runs $100,000–$200,000; a detached 500 sq ft ADU $180,000–$260,000; a 700–800 sq ft unit $225,000–$350,000; and a 1,000 sq ft unit $300,000–$450,000 or more. The rule of thumb is $300–$450 per square foot all-in, and $500 or more on difficult lots: hillside lots needing a geotechnical report, fire-zone lots built to Chapter 7A, and lots where the sewer lateral or a 100-amp panel must be replaced. End to end, plan on six months to a year. Our guide to how much it costs to build an ADU walks through a real 600 sq ft detached ADU whose budget rose from $180,000 to $265,000; the ADU service page covers how we run design, permitting and construction. To see how those costs compare with what an ADU rents for, read our ADU rental income guide, which uses HUD’s FY 2026 Fair Market Rents.

Frequently asked questions

What size ADU can I build anywhere in California?

In every California city, state law guarantees a detached ADU of at least 800 square feet and 16 feet tall with 4-foot side and rear setbacks on any lot with a house, regardless of local lot-coverage or floor-area limits. A city’s own cap must be at least 850 square feet for a studio or one-bedroom and 1,000 square feet for two or more bedrooms, and the statewide ceiling for a detached ADU is 1,200 square feet.

Which Southern California cities allow a 1,200 sq ft detached ADU?

Of the nine cities on this page, Los Angeles, Pasadena, Irvine, Anaheim and Corona allow a detached ADU of up to 1,200 square feet, though Pasadena cuts that to 1,000 square feet in its Hillside Overlay. Glendale caps units at 1,000 square feet, Burbank and Santa Clarita at 850 or 1,000 square feet by bedroom count, and Thousand Oaks allows one larger local-standard ADU within the 850 to 1,200 square foot band.

Do I need parking for an ADU in Southern California?

No city can require parking for an ADU converted from an existing house or garage, for a JADU, or for a unit within half a mile of public transit, and none can require you to replace the parking a garage conversion removes. For a larger new-construction unit outside those exemptions, most cities on this page may ask for one space, usually on the driveway; Anaheim exempts studios and the City of Los Angeles requires none for a state-law ADU.

Do I have to live on the property to build an ADU?

No. State law prohibits any owner-occupancy requirement for an ADU, and AB 976 made that prohibition permanent, so every city on this page lets you rent both the house and the ADU. A junior ADU is the exception: since January 2026 the owner must live in the house or the JADU only when the JADU shares a bathroom with the house, though some cities still record a covenant for every JADU.

Can my HOA stop me from building an ADU?

No. Under Civil Code 4751, any CC&R that effectively prohibits or unreasonably restricts an ADU or JADU on a single-family lot is void and unenforceable. The association can still apply reasonable architectural conditions on roof form, materials and colors, which is why in Irvine, Anaheim Hills, Corona and Thousand Oaks we get the HOA’s approval before the city submittal.

How long does it take to get an ADU permit in Southern California?

Every city must confirm within 15 business days whether an ADU application is complete and approve or deny it within 60 days of completeness, with no hearing, or it is deemed approved. Corrections, HOA review and utility clearances sit around that clock, and including design and construction an ADU in any of these cities typically takes six months to a year from first meeting to certificate of occupancy.

Find out what your lot allows before you pay for drawings

Send us the address and we will identify the jurisdiction, pull the zoning, fire-zone, hillside, historic and transit flags, and tell you the state-law floor and the city's own cap for your lot. Then we walk the site and give you a written, itemized estimate for the unit that fits; our office is at 16120 Sherman Way in Van Nuys, open every day from 8 AM to 6 PM.